Loschmidt-amplitude wave function spectroscopy and the physics of dynamically driven phase transitions

TL;DR

This paper introduces Loschmidt amplitude wave function spectroscopy as a novel method to analyze many-body wave functions, specifically applied to the quantum Ising model, revealing insights into defect populations, interactions, and quantum coherence effects.

Contribution

It presents a new spectroscopy technique using Loschmidt amplitude to study the dynamics of many-body wave functions during quantum phase transitions.

Findings

Confirmed previous results on defect populations

Clarified the role of quantum coherence

Analyzed effects of magnon-magnon interactions and finite-size corrections

Abstract

We introduce the Loschmidt amplitude as a powerful tool to perform spectroscopy of generic many-body wave functions and use it to interrogate the wave function obtained after ramping the transverse field quantum Ising model through its quantum critical point. Previous results are confirmed and a more complete understanding of the population of defects and of the effects of magnon-magnon interaction or finite-size corrections is obtained. The influence of quantum coherence is clarified.